Synthesis of green phosphor SrAl2O4: Eu2+, Dy3+: Rietveld refinement and optical properties

Strontium aluminate (SrAl2O4), SrAl2O4: Eu2+ and SrAl2O4: Eu2+/Dy3+ phosphors were prepared by solution combustion method. The XRD patterns of the sample were analysed using Rietveld refinement. The analysis confirmed the multiphase structure consisting of hexagonal (P63 space group) and monoclinic (P121 space group) phases. The refinement χ2 values in the range of 2.1–2.8. The crystal structure model was generated based on the refined data. The refined unit cell volume show increment after Eu and Dy doping. The estimated crystallite size is approximately 19 nm and slightly increase after calcination. The emission spectra of the Eu2+ doped SrAl2O4 sample shows a broad emission band with a peak around 500 nm, corresponding to 4f6 5d1 –4f7 transition. With additional Dy3+ doping, the emission peak shifted towards 522 nm, which emitted green light as illustrated by the CIE diagram. The synthesized compounds were also characterized by FTIR and UV-vis for their chemical bonding and energy band gap respectively.